A monument commemorating Ghetto fighters who escaped the Nazis through a sewer during the Warsaw ghetto uprising 70 years ago is pictured on April 18, 2013 in Warsaw. The Warsaw getto was established October 1940 as the largest of all Jewish gettos in Europe during World War II. AFP PHOTO/JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

Warsaw Ghetto survivor Jakub Gutenbaum, 83, speaks to The Associated Press in Warsaw, Poland, Thursday, April 18, 2013. Many decades since the ghetto uprising, Jakub Gutenbaum still squirms at the thought of scalding-hot walls in the basement he was hiding, as houses overhead were on fire. Talking to The Associated Press on Thursday, the 83-year-old Gutenbaum recalls how German troops came into his hiding place and forced everyone out at gunpoint. Gutenbaum, his mother and little brother, lived through the horror of the uprising, an against-all-odds-revolt by hundreds of lightly armed Jewish fighters against a much larger Nazi force that broke out 70 years ago on Friday. (AP Photo/Alik Keplicz)

89 year old Simcha "Kazik" Rotem (C) revisits on April 18, 2013 the sewer through which he and dozens of comrades escaped the Nazis during the Warsaw ghetto uprising 70 years ago. The Warsaw getto was established October 1940 as the largest of all Jewish gettos in Europe during World War II. AFP PHOTO/JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

Photo: Janek Skarzynski, AFP/Getty Images

89 year old Simcha "Kazik" Rotem (C) revisits on April 18, 2013 the...

89 year old Simcha "Kazik" Rotem (C) attends a commemoration ceremony on April 18, 2013 in Warsaw, after he revisited a sewer through which he and dozens of comrades escaped the Nazis during the Warsaw ghetto uprising 70 years ago. The Warsaw getto was established October 1940 as the largest of all Jewish gettos in Europe during World War II. AFP PHOTO/JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

Cantor Joseph Malovany sings a prayer in Warsaw's synagogue for the rights among the nations and for the victims of the Warsaw ghetto uprising on the eve of the uprising's 70th anniversary on April 18, 2013. The Warsaw ghetto was established in October 1940 as the largest of all Jewish ghettos in Europe during World War II. AFP PHOTO / JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

The reconstructed ceiling of a wooden-roofed synagogue is a highlight of one of the principal galleries in Warsaw's new Museum of the History of Polish Jews. (Photo courtesy of the Museum/MCT)

Photo: Handout, McClatchy-Tribune News Service

The reconstructed ceiling of a wooden-roofed synagogue is a...

The reconstructed ceiling of a wooden-roofed synagogue is a... Photo-4493247.60647 - SFGate

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Windows at Warsaw's new Museum of the History of Polish Jews are etched with interwoven Hebrew and Latin letters. (Roy Gutman/MCT)

Photo: Roy Gutman, McClatchy-Tribune News Service

Windows at Warsaw's new Museum of the History of Polish Jews are...

Windows at Warsaw's new Museum of the History of Polish Jews... Photo-4493244.60647 - SFGate

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The dramatic foyer at Warsaw's new Museum of the History of Polish Jews symbolizes the rupture in Jewish history caused by the Holocaust. (Roy Gutman/MCT)

Photo: Roy Gutman, McClatchy-Tribune News Service

The dramatic foyer at Warsaw's new Museum of the History of Polish...

The dramatic foyer at Warsaw's new Museum of the History of... Photo-4493243.60647 - SFGate

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Light pours into Warsaw's new Museum of the History of Polish Jews, designed by Finnish architect Rainer Mahlamaki. (Photo courtesy of the Museum/MCT)

Photo: Handout, McClatchy-Tribune News Service

Light pours into Warsaw's new Museum of the History of Polish Jews,...

Light pours into Warsaw's new Museum of the History of Polish... Photo-4493241.60647 - SFGate

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A man holding a daffodil takes a photo of a wall painting presenting Marek Edelman, the only Warsaw Ghetto 1943 Uprising commander who survived World War II, also holding a daffodil, on the eve of the 70th anniversary of the revolt, in Warsaw, Poland, Thursday, April 18, 2013. Daffodils, which bloom in April, the month the uprising began, are a symbol of remembrance and hope, and were distributed to visitors viewing the graffiti. (AP Photo/Alik Keplicz)

Photo: Alik Keplicz, Associated Press

A man holding a daffodil takes a photo of a wall painting...

A man holding a daffodil takes a photo of a wall painting... Photo-4493242.60647 - SFGate

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Cantor Joseph Malovany sings a prayer in Warsaw's synagogue for the rights among the nations and for the victims of the Warsaw ghetto uprising on the eve of the uprising's 70th anniversary on April 18, 2013. The Warsaw ghetto was established in October 1940 as the largest of all Jewish ghettos in Europe during World War II. AFP PHOTO / JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

An inside view of the Museum of the History of Polish Jews designed by Finnish architects Rainer Mahlamaeki and Ilmari Lahdelma, is pictured on April 18, 2013 In Warsaw. On April 19, 2013 the Museum of the History of Polish Jews will begin its educational and cultural programming in its new building with the commemoration of the 70th anniversary of the Warsaw Ghetto Uprising. AFP PHOTO/JANEK SKARZYNSKIJANEK SKARZYNSKI/AFP/Getty Images

Photo: Janek Skarzynski, AFP/Getty Images

An inside view of the Museum of the History of Polish Jews designed...

An inside view of the Museum of the History of Polish Jews designed... Photo-4493239.60647 - SFGate